A conventional swapping apparatus for use in computer systems swaps data between the main storage and the secondary storage. For one example of such an apparatus, reference may be made to Stuart E. Madnick and John J. Donovan, "Operating Systems", pp. 185-186.
Since such a swapping apparatus collectively handles inputs and outputs between the total memory contents and the secondary storage contained in a process, a separate secondary storage should be secured besides the secondary storage for the usual paging purpose. This entails the disadvantage of requiring a large secondary storage capacity.
As the whole memory contents contained in a process are always the object of collective inputting and outputting, the collective inputting and outputting can be expected to speed up the computer system if the total memory contents of the process make up a large volume. If the volume is not very large, however, there will be another disadvantage that the load of the inputting and outputting is too great, and the overall performance of the total system is made less efficient.
An object of the present invention is to provide a swapping apparatus which is free of these disadvantages, and designed to reduce the required capacity of the secondary storage and yet to improve the overall performance of the total system.